This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Friday, April 24, 2020

Death by Audio Sound Saw

Not quite a Fuzz Friday, but a Filter Friday I guess. Goes hand in hand with some fuzz though. The Sound Saw has two different passive filters selected by the Channel footswitch. The filters then share a 2-transistor gain recovery stage. Here's the schematic for reference. You can use a common cathode LED for the Channel switch or 2 individual LEDs if you prefer. See wiring diagram below. Laid this out for a 125B, but should be easy enough to adapt for 1590BB if you prefer. Will probably be doing a fabricated version of this in the near future as well.

Sound sample:



11 comments:

  1. Speaking of saw... could you make a one knob version of the boss HM-2? Greetings and thanks for so many contributions!!!!

    ReplyDelete
  2. Hello, I have a question: how do you build the pedals? Are the original circuits the ones you use, or do you design them trying to be as similar as possible to the original ones?

    Greetings from Agentina !. I admire everything you are doing. I am very happy to have found this page, I just have to start putting together some of your hundreds designs for my guitar!

    ReplyDelete
    Replies
    1. He probably uses original circuits,making layouts from orig. schematics..this site is truly awesome, I built few very nice projects from here

      Delete
  3. Speaking of Hyper Fuzz, I wonder how there is still no BOSS FZ-2 layout on this blog! :D

    I had a Behringer SF-300 and it's almost entirely SMD inside. Tried to rehouse it, but said "f*ck it" in the middle of the process, after desoldering some of the components. xD
    I won't recommend anyone to do it, just build new one from scratch!

    Also, please please please bring fuzz fridays back! Greetings from Russia and thanks for all your hard work! You are my favorite source of DIY pedal layouts!

    ReplyDelete
  4. Just made one and... it doesn't work. I've checked each connection twice, everything is right. No links between traces. What can be wrong?

    ReplyDelete
    Replies
    1. Signal flows when bypassed. When effect is on, 1st mode works strange: very distorted high-pitched sound (like a gated fuzz with hp-filter), volume and filter knobs affect a "gate" but don't work as the volume and the filter. 2nd mode doesm't work at all.

      And the signal is very hot, my audio interface almost clipping on it's lowest gain. Checked with Volca FM, i have no guitar for now

      Delete
    2. And i used 4007 diode instead 4001

      Delete
  5. Just built one.
    Doesn’t work the way I believe it’s supposed to.
    Damn certain I followed the off board wiring instructions correctly.

    Doesn’t get much guitar signal through at all, unless I put something like an IC big muff with volume waaaaaay up, and then I get the kind of behavior described above. Channel A passes signal but the controls don’t behave like a volume or filter really and Channel B barely passes anything at all.

    I just got back to building after a short hiatus and am too lazy to go over the schematic and compare with the pcb you’ve made. I might get to it in a month or two.

    ReplyDelete
  6. Looks like someone on the vero site got this to work by flipping the transistors to the conventional orientation (emitter facing ground, collector facing positive voltage), rather than the way they are drawn on the schematic.

    ReplyDelete
  7. Verified, but the top 10k resistor (Q2 base to voltage) should be 100k.

    The transistors work in the "backwards" orientation, as on the schematic. However, the circuit is a bit picky with transistor choice. I tried a variety of BJT's at random, but most left the circuit with below-unity volume with most of the filter settings. A few passed no signal or had the heavy gating behavior described by other posters. I got my best results with 2N5088's from Small Bear and some BC550's from either Tayda or Mouser.

    With how inconsistent this one is, maybe a better, smaller choice would be a BMP tone stack with a mid-control mod, followed by your booster of choice.

    ReplyDelete